Electro-optical module, power supply substrate, wiring substrate, and electronic apparatus

ABSTRACT

This invention provides an electro-optical module with reduced noise in driving voltage. The invention can include a power supply substrate that is arranged separately from the flexible substrate having a driver, so that the noise of the driving voltage supplied from the power supply substrate is reduced.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to an electro-optical module, a power supplysubstrate, a wiring substrate, and an electronic apparatus.

2. Description of Related Art

A type for mounting an electro-optical panel having an electro-opticalelement, such as a liquid crystal device, on an electronic apparatus,such as cellular phone and television has been known in the related art.See, for example, Japanese Unexamined Patent Application Publication No.10-209581.

In order to safely drive the electro-optical element on theelectro-optical panel, a method for mounting the electro-optical panel,a method for connecting the electro-optical panel to a wiring substrate,configuration or structure of the electro-optical module need to beconsidered in addition to the configuration of the electro-optical panelitself. As the electro-optical panel has been densely integrated,problems, such as noise or a delay, in control signal or instability ofthe driving voltage need to be solved in consideration of the mountingtype.

An object of the invention is to provide the electro-optical module andrelated components which are designed to solve the above-mentionedproblem.

SUMMARY OF THE INVENTION

The first electro-optical module of the invention can include anelectro-optical panel having a plurality of electro-optical elements, awiring substrate connected to the electro-optical panel and having adriver for generating a signal to be supplied to the electro-opticalpanel, and a power supply substrate for generating a panel drivingvoltage for driving the plurality of electro-optical elements. The paneldriving voltage can be supplied to the electro-optical panel through thewiring substrate. In the electro-optical module, the wiring substratehaving the driver and the power supply substrate may be separatelyarranged, so that only the power supply substrate may be examined tofacilitate detection of operational faults.

When the function of the driver and the function of the power supplycircuit are integrated as integrated circuits (IC), all of ICs need tobe replaced with good ones when some functions as mentioned above aredetected to be faulty, however, the function of the power supplysubstrate is installed in the power supply circuit separate from thewiring substrate with the driver, as is done in the electro-opticalmodule of the invention, only the power supply substrate may be replacedwith a good one when the function of the power supply circuit isdetected to have operational faults.

In addition, the term electro-optical panel means a panel havingelectro-optical elements and is represented by, for example, a displaypanel such as a liquid crystal panel or an organic electroluminescent(EL) panel. The term electro-optical module means one having anelectro-optical panel and is represented by, for example, a liquidcrystal module or an organic EL module.

In the above-mentioned electro-optical module, it is preferable that thepanel driving voltage be supplied to the electro-optical panel, notthrough the driver but through driving voltage wiring formed in thewiring substrate. With this configuration, problems such as instabilityof the panel driving voltage, signal slowdown, or signal delay due tointerference between the panel driving voltage supplied to theelectro-optical panel, and data signal, clock signal, or the like forcontrolling the electro-optical panel generated in the driver may bereduced.

In the electro-optical module, it is preferable that the power supplysubstrate further generate a driver driving voltage for driving thedriver, and the driver driving voltage be supplied to the driver. Oneadvantage of the electro-optical module may be to replace the powersupply substrate with a new one having a desired specification, whichallows it to adjust the driver driving voltage.

In the electro-optical module, a reference voltage used for generatingthe panel driving voltage and a driver control signal for controllingthe driver in the power supply substrate are supplied from outsidethrough a first connector formed in the wiring substrate, and thereference voltage is supplied to the power supply substrate through asecond connector different from the first connector formed in the wiringsubstrate.

In the above-mentioned electro-optical module, the term referencevoltage may include ground potential, or voltage of a battery powersupply supplied from an external device such as a body of a cellularphone or the like.

In the above-mentioned electro-optical module, the panel driving voltageor the driver driving voltage is generated based on the ground potentialand the voltage of the battery power supply.

In the above-mentioned electro-optical module, the panel driving voltageor the driver driving voltage may be supplied from the power supplysubstrate through the second connector and the wiring substrate.

In the above-mentioned electro-optical module, it is preferable that awiring length ranging from the first connector to the second connectorof reference voltage wiring formed in order to supply the referencevoltage to the power supply substrate be shorter than that of drivercontrol signal wiring for supplying the driver control signal from thefirst connector to the driver. In other words, the reference voltagewiring is preferably dragged for a short distance. By thisconfiguration, instability of the reference voltage supplied fromoutside may be reduced.

In the above-mentioned electro-optical module, it is preferable that aline width of the reference voltage wiring be larger than that of thedriver control signal wiring. By this configuration, problems, such asvoltage drop resulting when the reference voltage reaches the powersupply substrate, may be reduced.

The invention can provide a power supply substrate for generating anelectro-optical panel driving voltage or a driving voltage to besupplied to a driver for driving the electro-optical panel, based on areference voltage supplied from outside, having a first conductive layerfor transmitting the driving voltage, in which at least a portion isformed of a first conductive material, and a second conductive layer fortransmitting the reference voltage, in which at least a portion isformed of a second conductive material, wherein the first conductivelayer and the second conductive layer are separated from each other byat least one insulating layer.

In other words, conductive layers containing conductive material arestacked, which allows the area occupied by the power supply substrate tobe reduced. In addition, the first conductive layer may have anelectronic circuit for generating the driving voltage.

In the above-mentioned power supply substrate, it is preferable tofurther include a third conductive layer of which at least a portion isformed of a third conductive material and which is connected to apredetermined potential. The predetermined potential refers to, forexample, a voltage of the above-mentioned ground potential or a voltageof a battery power supply.

In the electro-optical module where this power supply substrate isoverlapped with signal wirings for transmitting data signals, noise maybe blocked by the third conductive layer even if the signal wirings actas a noise source, which leads to suppression of the instability of thedriving voltage. This effect may be further improved by increasing thearea that the third conductive material occupies in the third conductivelayer.

The invention provides a wiring substrate having a driver for generatinga driving signal for driving a plurality of electro-optical elements inan electro-optical panel having the plurality of electro-opticalelements, including a first connector for connecting an external deviceto the wiring substrate and a second connector for connecting a powersupply substrate for generating a driving voltage for driving theplurality of electro-optical elements to the wiring substrate.

In the above-mentioned wiring substrate, for example, a signal orvoltage, such as a control signal supplied to the driver or referencevoltage, which are supplied from an external device, such as a body of acellular phone, are supplied to the wiring substrate through the firstconnector, and voltage generated in the power supply substrate such as apanel driving voltage or a driving voltage for driving the driver aresupplied to the wiring substrate through the second connector. A signalfor controlling the power supply substrate through the second connectormay be further supplied from the driver through the power supplysubstrate.

In the above-mentioned wiring substrate, it is preferable that theplurality of electro-optical elements be arranged between a plurality ofpixel electrodes corresponding to the plurality of electro-opticalelements, respectively, and a common electrode formed in common for theplurality of pixel electrodes, the wiring substrate further comprisefirst wiring for supplying the common voltage and second wiring forsupplying a driving voltage to the plurality of pixel electrodes, and aline width of the first wiring be larger than that of the second wiring.By this configuration, a voltage may be safely supplied to the commonelectrode.

In the above-mentioned wiring substrate, the term common electrode meansan opposite electrode that is arranged to face the pixel electrode. Whenthe opposite electrode is negative, the potential of the commonelectrode is ground potential.

In the above-mentioned wiring substrate, it may be that the plurality ofelectro-optical elements can include a red electro-optical element, agreen electro-optical element, and a blue electro-optical element, theplurality of electro-optical elements are arranged between a pluralityof pixel electrodes corresponding to the plurality of electro-opticalelements, respectively, and a common electrode formed in common for theplurality of pixel electrodes, the wiring substrate further comprisesfirst wiring for supplying the common voltage,red-electro-optical-element wiring for supplying a driving voltage to apixel electrode corresponding to the red electro-optical element,green-electro-optical-element wiring for supplying a driving voltage toa pixel electrode corresponding to the green electro-optical element,and blue-electro-optical-element wiring for supplying a driving voltageto a pixel electrode corresponding to the blue electro-optical element,and a line width of at least one wiring of thered-electro-optical-element wiring, the green-electro-optical-elementwiring, and the blue-electro-optical-element wiring is different fromthe others.

In the above-mentioned wiring substrate, it is preferable that theplurality of electro-optical elements include a red electro-opticalelement, a green electro-optical element, and a blue electro-opticalelement, the plurality of electro-optical elements be arranged between aplurality of pixel electrodes corresponding to the plurality ofelectro-optical elements, respectively, and a common electrode formed incommon for the plurality of pixel electrodes, the wiring substratefurther comprise first wiring for supplying a common voltage,red-electro-optical-element wiring for supplying a driving voltage to apixel electrode corresponding to the red electro-optical element,green-electro-optical-element wiring for supplying the driving voltageto the pixel electrode corresponding to the green electro-opticalelement, and blue-electro-optical-element wiring for supplying thedriving voltage to the pixel electrode corresponding to the blueelectro-optical element, and a line width of each type of thered-electro-optical-element wiring, the green-electro-optical-elementwiring and the blue-electro -optical-element wiring be set according tothe luminous efficiencies of the corresponding electro-optical elements.

When property or spectral luminous efficiency changes in response tocolor of the electro-optical element, the wiring substrate may allow thewiring widths to be adjusted based on the conditions, so that thereexists an advantage in compensating the property or the spectralluminous efficiency.

In the above-mentioned wiring substrate, it may be that the plurality ofelectro-optical elements include a red electro-optical element, a greenelectro-optical element, and a blue electro-optical element, theplurality of electro-optical elements are arranged between a pluralityof pixel electrodes corresponding to the plurality of electro-opticalelements, respectively, and a common electrode formed in common for theplurality of pixel electrodes, the wiring substrate further comprisesfirst wiring for supplying a common voltage, red-electro-optical-elementwiring for supplying a driving voltage to a pixel electrodecorresponding to the red electro-optical element,green-electro-optical-element wiring for supplying the driving voltageto the pixel electrode corresponding to the green electro-opticalelement, and blue-electro-optical-element wiring for supplying thedriving voltage to the pixel electrode corresponding to the blueelectro-optical element, and a line width of the red-electro-optical-element wiring is larger than those of the greenelectro-optical element and the blue electro-optical element.

The line width of the red-electro-optical-element wiring may beincreased as in the wiring substrate, and thus the luminance of the redelectro-optical element may be compensated even if the luminousefficiency of the red electro-optical element is relativelydeteriorated.

In the above-mentioned wiring substrate, it is preferable that theplurality of electro-optical elements can include a red electro-opticalelement, a green electro-optical element, and a blue electro-opticalelement, the plurality of electro-optical elements be arranged between aplurality of pixel electrodes corresponding to the plurality ofelectro-optical elements, respectively, and a common electrode formed incommon for the plurality of pixel electrodes, the wiring substratefurther comprise first wiring for supplying a common voltage,red-electro-optical-element wiring for supplying a driving voltage to apixel electrode corresponding to the red electro-optical element,green-electro-optical-element wiring for supplying the driving voltageto the pixel electrode corresponding to the green electro-opticalelement, and blue-electro-optical-element wiring for supplying thedriving voltage to the pixel electrode corresponding to the blueelectro-optical element, and a line width of the green-electro-optical-element wiring be narrower than those of thered-electro-optical-element wiring and the blue-electro-optical-elementwiring.

In this way, the line width of the green-electro-optical-element wiringmay be relatively reduced, which allows to compensate the luminance ofthe green pixel even if the luminous efficiency of the greenelectro-optical element is high.

In the above-mentioned wiring substrate, it is preferable that thewiring substrate be flexible, and at least a portion thereof be bent.

In the above-mentioned wiring substrate, a notch having three sides canbe preferably formed in at least a portion of the wiring substrate. Forexample, three upper sides may be formed to a structure such as a driverformed in the wiring substrate. By this configuration, the structure maynot be bent or damaged even when the wiring substrate is bent.

The second electro-optical module of the invention can include theabove-mentioned wiring substrate, and an electro-optical panel connectedto the wiring substrate, the wiring substrate and the electro-opticalpanel are connected to a connecting portion at one side of a pluralityof sides forming the periphery of the electro-optical panel, the wiringsubstrate comprises a first portion, and a second portion formed bybending the wiring substrate and facing the first portion, the firstportion is formed through a supporting member for supporting theelectro-optical panel at a second main surface which is opposed to afirst main surface existing in a direction where light of theelectro-optical panel is emitted, the second portion is formed to allowthe first portion to be interposed between the second main surface andthe second portion, and the driver is interposed between the firstportion and the second portion.

In other words, in the electro-optical module, a side which is opposedto a direction emitting light in the electro-optical module, that is,the rear surface of the electro-optical panel, is used, so that thewiring substrate is attached to the rear surface, thereby effectivelyutilizing space. Furthermore, the driver is interposed within the wiringsubstrate having a bent structure in the electro-optical module, whichallows influence due to external factors such as mechanical power,light, or heat to be reduced.

In the above-mentioned electro-optical module, it is preferable that afirst connector and a second connector be arranged in the secondportion.

In the above-mentioned electro-optical module, it is preferable that abase and a first protrusion protruding from the base be formed in thesecond portion, and the first connector be arranged at an edge of thefirst protrusion.

In the above-mentioned electro-optical module, the first protrusion ispreferably formed to be protruded from a side in which a connectingportion for connecting the electro-optical panel to the wiring substrateis located, of a plurality of sides forming the periphery of theelectro-optical panel than a position to which the base of the secondprotrusion is attached. By this configuration, connection to an externaldevice, such as a cellular phone, may be facilitated.

In the above-mentioned electro-optical module, it is preferable that asecond protrusion protruding from the base be formed in the secondportion, and the second connector be arranged at an edge of the secondprotrusion.

In the above-mentioned electro-optical module, a distance from the baseto the edge of the first protrusion is preferably longer than that fromthe base to the edge of the second protrusion.

In the above-mentioned electro-optical module, a position where the baseof the first protrusion is attached to is preferably formed closer toany one of two sides crossing with a side in which the connectingportion is located, of a plurality of sides forming the periphery of theelectro-optical panel than a position to which the base of the secondprotrusion is attached.

In other words, the root position in the base of the second protrusionis preferably arranged at the center rather than that in the base of thefirst protrusion.

In the above-mentioned electro-optical module, it is preferable that itfurther include a power supply substrate connected through the secondconnector. The power supply substrate be formed in the second mainsurface through the supporting member and the first portion of thewiring substrate, and be arranged closer to the connecting portion ofthe electro-optical panel than the second connector.

As will be described later, when the driver is formed close to theconnecting portion between the driver and the electro-optical panel, aninterval between a plurality of wirings for connecting the driver to theconnecting portion becomes larger when it is closer to the connectingportion. In other words, the distance between the wirings becomesshorter, and the distances of the plurality of wirings become differentfrom one another, which causes time-based errors among signalstransmitted through the wirings.

Therefore, the driver is preferably spaced by using a predetermineddistance from the connecting portion between the driver and theelectro-optical panel.

However, the space between the driver and the connecting portion forconnecting the driver to the electro-optical panel becomes useless inthe wiring substrate at one side thereof. As a result, this unused spaceis utilized in the electro-optical module of the present invention tothereby form the power supply substrate, which leads to effectiveutilization of the rear surface of the electro-optical panel.

In the above-mentioned electro-optical module, it is preferable that thesupporting member be attached to the power supply substrate by adetachable mechanism. In the above-mentioned electro-optical module, thepower supply substrate may be readily detached and replaced with a goodone when it is detected to have a fault. In addition, it may be replacedwith the power supply substrate having a desired specification, ifnecessary.

The electronic apparatus of the present invention can include theabove-mentioned electro-optical module.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numerals reference like elements, and wherein:

FIG. 1 shows a configuration of a rear surface of a display moduleaccording to an embodiment of the present invention;

FIG. 2 shows a cross-sectional structure of a display module accordingto the embodiment of the present invention;

FIG. 3 shows a cross-sectional structure of a power supply substrateaccording to the embodiment of the present invention;

FIG. 4 shows an assembly view of the display module according to theembodiment of the present invention;

FIG. 5 shows a planar structure of a flexible substrate according to theembodiment of the present invention;

FIG. 6 shows a schematic view of a wiring structure of the flexiblesubstrate according to the embodiment of the present invention;

FIG. 7 shows a schematic view of the wiring structure of the flexiblesubstrate according to the embodiment of the present invention;

FIG. 8 shows a schematic view of the wiring structure of the flexiblesubstrate according to the embodiment of the present invention;

FIG. 9 shows a view for explaining an electronic apparatus according tothe embodiment of the present invention;

FIG. 10 shows a view for explaining an electronic apparatus according tothe embodiment of the present invention; and

FIG. 11 shows a view for explaining an electronic apparatus according tothe embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A display module M consists of a flexible substrate, a display panel P,and a frame SF for supporting the display panel P. FIG. 1 shows aconfiguration of a rear side of the display module (which is theopposite side of the display). FIG. 2(A) and FIG. 2(B) show crosssectional views taken along the line X-X′ line and the line Y-Y′ line ofFIG. 1, respectively. In the rear side of the display module M as shownin FIG. 1, a flexible substrate F having a driver D1 and an auxiliarydriver D2, and a power supply substrate B are arranged.

The driver D1 is interposed between two portions of the flexiblesubstrate F bent as shown in FIG. 2(B). The driver D1 generates a datasignal, a precharge signal, a clock signal, a check signal, a controlsignal for controlling scanning line driving circuit, a control signalfor controlling a driving voltage to be supplied to the driver D1 itselfand the display panel P, or the like.

The auxiliary driver D2 has a notch (which corresponds to a notch to bedescribed below with reference to FIG. 5) arranged in a region outsidethe above-mentioned bent portion of the flexible substrate F, so thatthe driver D2 is arranged in a developed portion. The auxiliary driverD2 is not covered by any portions of the flexible substrate F butexposed. The auxiliary driver D2 has a memory, a personal computer, andthe like, so that it acts to support the operation of the driver D1.

The power supply substrate B mostly generates a driving voltage for thedisplay panel including a pixel circuit, scanning line driving circuit,check circuit or the like, or a driving voltage for driving the driverD1.

The power supply substrate B can be connected to the flexible substratethrough a second connector C2, and is fixed to the frame SF by means ofdevices to be described below. The flexible substrate F is connected tothe display panel P to be bent from the side close to the power supplysubstrate B of the display panel P, and by this structure, the powersupply substrate B is arranged near the connecting portion of theflexible substrate F and the display panel P closer than the driver D1.

A wiring pattern arranged from the driver to the electro-optical panelhas a fan shape or a similar shape, and has the widened fan shape whenthe driver is arranged close to the connecting portion of theelectro-optical panel and the driver. In other words, a large distanceoccurs between the wiring length positioned at a center portion and thewiring length positioned at an end. Owing to this, time-lag occursbetween signals transmitted through the wiring. Therefore, the drivercan be preferably arranged to be spaced from the connecting portion ofthe driver and the electro-optical panel by a predetermined distance.

In the meantime, the space between the driver and the connecting portionof the driver and the electro-optical panel becomes useless in a wiringsubstrate. Thus, in the electro-optical module according to theembodiment, this useless space is utilized to arrange the power supplysubstrate B, so that the space of the rear side of the electro-opticalpanel becomes useful.

As mentioned above, the driver D1 and the power supply substrate B arearranged not to be overlapped, which allows the thickness of the crosssectional direction of the display module M to be reduced.

In addition, the power supply substrate B can be connected to theflexible substrate F as shown in FIG. 2, however, the power supplysubstrate B may be spaced from the flexible substrate F so as toeffectively scatter off heat generated from the power supply substrateB.

The frame SF is formed of a metal material, and by thermal conductivityof the metal material, heat generated by an electric conduction to thedisplay panel P, or the like, is radiated outside the frame.Furthermore, the frame SF has a plurality of holes H to further improvea heat radiation effect.

Next, a cross sectional structure of the power supply substrate B willbe described. The power supply substrate B has a multi-layered structureincluding a plurality of conductive layers. In the embodiment,specifically, it has four layers, which consists of a first conductivelayer L1, a second conductive layer L2, a third conductive layer L3, anda fourth conductive layer L4, which are arranged in an order closer tothe connecting portion of the connector C2. Any of the first conductivelayer L1 to the fourth conductive layer L4 has at least a portion formedof a conductive material. A first insulating layer I1, a secondinsulating layer I2, and a third insulating layer I3 are interposedbetween the first conductive layer L1 and the second conductive layerL2, between the second conductive layer L2 and the third conductivelayer L3, and between the third conductive layer L3 and the fourthconductive layer L4, respectively. As is not shown in the figure, eachof these insulating layers has a contact hole formed to have theelectric connection between the upper side and the lower side thereof.

A power supply voltage V and a ground potential G, which are suppliedfrom an external device through the connector C1 to the display moduleM, are supplied to the second conductive layer L2 and the thirdconductive layer L3, respectively. The first conductive layer L1 is usedas a conductive layer for conducting a panel driving voltage VP for thedisplay panel P generated based on the reference voltage V and theground potential G, or a driver driving voltage VD for the driver D1 orthe auxiliary driver D2, and the panel driving voltage VP and the driverdriving voltage VD are supplied to the display panel P through theconnector C2 and the flexible substrate F.

The fourth conductive layer L4 of the lowest layer, which corresponds tothe rear surface of the power supply substrate B, can be arranged tohave a predetermined potential. In the embodiment, all of a rear surfaceof the power supply substrate B is formed of conductive material.

In the display module M, a signal wiring for supplying signals, such asdata signal and clock signal, from the driver D1 to the display panel Pis arranged close to the fourth conductive layer L4, which is set tohave a predetermined potential as mentioned above, so that influencesregarding the power supply substrate B, such as variation or noise ofthe potential which passes through the signal wiring may be blocked bythe fourth conductive layer L4. By means of this structure, the paneldriving voltage generated from the power supply substrate B may besafely supplied to the display panel P.

In the embodiment, any of the first conductive layer L1 to fourthconductive layer L4 can be formed of a copper thin film.

Next, a configuration of the display module M will be described withreference to FIG. 4. A circular polarization film CPF is arranged in amain surface of a display surface (a direction where light is emitted)of the display panel P. The frame SF is attached to a side which isopposed to the main surface of the display surface side of the displaypanel P by an attachment tape AT3.

The flexible substrate F is attached to the main surface of the sidewhich is opposed to the main surface of a side to which the displaypanel P is attached in the frame SF, by an attachment tape AT2. Thedriver D1 and the auxiliary driver D2 are arranged in a first mainsurface of the side which is opposed to the main surface of the frame SFside in the flexible substrate F as mentioned above. The driver D1 isinterposed between the first main surface of the flexible substrate Fand the portion where the flexible substrate F is bent, and theattachment tape AT1 is interposed between the driver D1 and the bentportion.

The power supply substrate B is arranged in the first main surface ofthe flexible substrate F through an insulating tape IT1. Furthermore,the power supply substrate B is fixed by a mechanism for inserting aprotrusion Q formed in the power supply substrate B into a hole formedin a protrusion W of the frame SF. In the meantime, electricalconnection is implemented by connecting a connector C2 (A) formed in theflexible substrate F to a connector C2 (B) formed in the power supplysubstrate B. By using such a simple mechanism, the power supplysubstrate B can be fixed while it is electrically connected thereto, sothat the power supply substrate B may be readily replaced with a new onewhen it is determined to have a fault. In addition, the power supplysubstrate B having different performance such as output of drivingvoltage or the like may readily replaced with a new one.

In addition, the power supply substrate B is arranged separately fromthe driver D1, so that a dedicated terminal for checking may be arrangedfor each of the driver D1 and the power supply substrate B. As a result,factor of the problem may be checked in a short time, and thus it ispossible to relatively perform the performance evaluation of the powersupply substrate B and the driver D.

Referring to FIG. 5, a detailed structure of the flexible substrate Fwill be described.

As mentioned above, a notch K is formed in the flexible substrate Falong at least a portion of at least a side of the auxiliary driver D2and two sides crossing with the side. By means of this structure, theauxiliary driver D2 is not bent even if the flexible substrate F is bentas shown in FIG. 2.

The connector C1 for connection with the flexible substrate F is formedat an edge of a first protrusion U1 protruding from the base of theflexible substrate, and the connector C2 formed for connection with theflexible substrate F is formed at an edge of a second protrusion U2protruding from the base of the flexible substrate. As apparent fromFIG. 5, a distance from the connector C1 to the root portion of thefirst protrusion is longer than that from the connector C2 to the rootportion of the second protrusion. By this structure, as seen from FIG. 1described above, the connector C1 is protruded from the periphery of thedisplay panel P when the display panel P and the flexible substrate areconnected to each other to be mounted. Since the connector C1 isprotruded from the display panel P, the connection between the connectorC1 and an external device may be sterically facilitated.

The flexible substrate F includes a wiring WG for supplying a groundpotential G to the display panel P, a wiring WR for supplying a drivingvoltage for red pixel (a red electro-optical element) to the displaypanel P, a wiring WGr for supplying a driving voltage for green pixel (agreen electro-optical element) to the display panel P, and a wiring WBfor supplying a driving voltage for blue pixel (a blue electro-opticalelement) to the display panel P. The wiring WG, among theabove-mentioned wirings, is formed at the outermost of the flexiblesubstrate F, and the wiring WG, wiring WR, wiring WGR, and wiring WB areformed in this order from the periphery of the flexible substrate F.

The wiring WG is connected to a common electrode that is formed to facethe pixel electrode in the display panel P, which leads to increase aline width of the wiring WG so as to reduce the wiring resistance. As aresult, the wiring WG has a line width larger than that of any of thewirings WR, WGr, and WB.

The line widths of the wirings WR, WGr, and WB may be properly adjustedin consideration of the property or color balance of an organicelectroluminescent (EL) element arranged in a pixel, and luminousefficiency of the organic EL element for red pixel employed in thepresent embodiment is relatively lower than that for green pixel, andthe line width is set to be WR>WB>WGr in consideration of the colorbalance or the like.

Next, transmitting path for various signals, such as various voltagesand data signals, in the display module M will be described withreference to schematic views of FIGS. 6 to 8.

Supplying the ground potential G will be described with reference toFIG. 6. The ground potential G supplied from the external device Ethrough the connector C1 is supplied to the driver D1, the auxiliarydriver D2, and the display panel P. Furthermore, it is supplied throughthe second connector C2 to the power supply substrate B formedseparately from the flexible substrate F.

A driving voltage supplied to the driver D and the display panel P willbe described with reference to FIG. 7. The power supply voltage Vsupplied from the external device E through the connector C1 is firstinput to the power supply substrate B through the second connector C2.The power supply substrate B generates a driver driving voltage VDsupplied to the driver D and a panel driving voltage VP supplied to thedisplay panel P, based on the power supply voltage V and theabove-mentioned ground potential G.

The driver driving voltage includes, for example, a reference voltage ofD/A converter, a precharge voltage, or a driving voltage for scanningline driving circuit.

In the meantime, the panel driving voltage VP is supplied not throughthe driver D1, but directly supplied to the display panel. The paneldriving voltage VP includes, for example, driving voltages for drivingthe electro-optical elements. These driving voltages are supplied to thedisplay panel P through the wiring WR for supplying the driving voltagefor red pixel (the red electro-optical element) to the display panel P,the wiring WGr for supplying the driving voltage for green pixel (thegreen electro-optical element) to the display panel P, and the wiring WBfor supplying the driving voltage for blue pixel (the blueelectro-optical element) to the display panel P, as described withregard to FIG. 5.

A control signal SP supplied from the driver D1 is employed to adjustthe generation or the level of the driver driving voltage VD or thepanel driving voltage VP. As the control signal SP, for example, dataregarding the usage circumstance, such as degradation or temperature ofthe electro-optical element of the display panel P is supplied to thepower supply substrate B, so that the panel driving voltage VP or thedriver driving voltage VD may be initially set at shipment or reset inthe field.

For example, when the display panel P consists of organic EL elementsfor red (R), green (G), and blue (B), having different luminous colors,the driving voltage of the organic EL elements may be adjusted inresponse to color balance adjustment, temporal variation, or usagecircumstance, so that the control signal SP generated as mentioned abovemay be supplied to the power supply substrate B, which leads to properlyadjust the level of the panel driving voltage VP.

In addition, when it is necessary to adjust the data signal supplied tothe display panel P based on the above-mentioned conditions, the controlsignal SP may be supplied to the power supply substrate B, therebychanging or adjusting the reference voltage of the D/A converter.

Next, supplying the control signal for controlling the driver D will bedescribed with reference to FIG. 8. The control signal S supplied fromthe external device E through the first connector C1 is input to thedriver D1. The control signal S, for example, includes, digital data forperforming D/A conversion, a clock signal for controlling timing as areference signal, a signal for generating a scanning signal or the like.The driver D1 generates the above-mentioned various signals to besupplied to the display panel P based on the control signal S.

By the configurations shown in FIGS. 6 to 8, following effects may beobtained. To detail this, the power supply voltage V input from theexternal device E is not input to the driver D but input to the powersupply substrate B through a short path such as the connector C2, whichleads to reduce voltage drop due to wiring dragging or influence fromexternal variation factors of voltage.

In the present embodiment, specifically, a wiring distance from theconnector C1 to the power supply substrate B of the wiring formed inorder to supply the power supply voltage V or the ground potential G isset to be shorter than that from the connector C1 to the driver D1 ofthe wiring formed in order to supply the control signal S.

In addition, the wiring width ranging from the connector C1 to the powersupply substrate B of the wiring formed in order to supply the powersupply voltage V or the ground potential G is set to be larger than thatranging from the connector C1 to the driver D1 of the wiring for controlsignal S. By this configuration, problems such as voltage drop of thepower supply voltage V or noise occurrence may be reduced.

The above-mentioned display module may be mounted in various electronicapparatuses including a mobile type personal computer, cellular phone,digital still camera or the like. FIG. 9 shows a perspective view of theconfiguration of a mobile type personal computer. The personal computer1000 can include a body 1040 having a keyboard 1020, and a display 1060using the display module in accordance with the embodiment of theinvention.

FIG. 10 shows a perspective view of the cellular phone. The cellularphone 2000 includes a plurality of operating buttons 2020, a sender2040, a receiver 2060, and a display 2080 using the display module inaccordance with the embodiment of the invention.

FIG. 11 shows a perspective view of a configuration of the digital stillcamera 3000. In addition, this figure readily shows connection betweenthe digital still camera and an external device. A typical camera isphotosensitive to a film by the use of light image of an object, whereasthe digital still camera 3000 generates an image pickup signal by usingphotoelectric conversion of an image pickup device, such as ChargeCoupled Device (CCD) for the light image of the object. In this case, adisplay 3040 using the display module in accordance with the embodimentof the present invention is arranged in the rear surface of the case3020 of the digital still camera 3000, so that display is performedbased on the pickup signal by the CCD. With this configuration, thedisplay 3040 acts as a finder for displaying the object. In addition, alight receiving unit 3060 including optical lens or CCD is arranged inthe observation side (which is the rear side thereof in the same figure)of the case 3020.

When a photographing user recognizes an image of the object displayed inthe display panel 3040 to press a shutter button 3080, the pickup signalof the CCD at this time is transmitted and stored to a memory of acircuit substrate 3100. In addition, a video signal output terminal 3120and an input/output terminal 3140 for data communication are arranged inthe side of the case 3020 in the digital still camera 3000. The formervideo signal output terminal 3120 is connected to a television monitor4300 and the latter input/output terminal 3140 for data communication isconnected to the personal computer 4400, if necessary as shown in thefigure. In addition, by using a predetermined operation, the pickupsignal stored in the memory of the circuit substrate 3100 is output tothe television monitor 4300 or the personal computer 4400.

In addition, the electronic apparatus may include not only the personalcomputer of FIG. 9, the cellular phone of FIG. 10, the digital stillcamera of FIG. 11, but also television, view finder type or monitordirect viewing type video tape recorder, car navigation device, pager,electronic notebook, electronic calculator, word processor, workstation,picture phone, Point of Sale (POS) terminal, device having touch panel,and the like.

While this invention has been described in conjunction with the specificembodiments thereof, it is evident that many alternatives,modifications, and variations will be apparent to those skilled in theart. Accordingly, preferred embodiments of the invention as set forthherein are intended to be illustrative, not limiting. There are changesthat may be made without departing from the spirit and scope of theinvention.

1. An electro-optical module, comprising: an electro-optical panelhaving a plurality of electro-optical elements; a wiring substratecoupled to the electro-optical panel and having a driver that generatesa signal to be supplied to the electro-optical panel; and a power supplysubstrate that generates a electro-optical panel driving voltage thatdrives the plurality of electro-optical elements, the electro-opticalpanel driving voltage being supplied to the electro-optical panelthrough the wiring substrate.
 2. The electro-optical module according toclaim 1, the panel driving voltage being supplied to the electro-opticalpanel, not through the driver, but through driving voltage wiring formedin the wiring substrate.
 3. The electro-optical module according toclaim 1, the power supply substrate further generating a driver drivingvoltage that drives the driver, and the driver driving voltage beingsupplied to the driver.
 4. The electro-optical module according to claim1, a reference voltage used for generating the panel driving voltage anda driver control signal that controls the driver in the power supplysubstrate being supplied from outside through a first connector formedin the wiring substrate, and the reference voltage being supplied to thepower supply substrate through a second connector different from thefirst connector formed in the wiring substrate.
 5. The electro-opticalmodule according to claim 4, the panel driving voltage or the driverdriving voltage being supplied from the power supply substrate throughthe second connector and the wiring substrate.
 6. The electro-opticalmodule according to claim 4, a wiring length ranging from the firstconnector to the second connector of reference voltage wiring formed inorder to supply the reference voltage to the power supply substratebeing shorter than that of driver control signal wiring that suppliesthe driver control signal from the first connector to the driver.
 7. Theelectro-optical module according to claim 6, a line width of thereference voltage wiring being larger than that of the driver controlsignal wiring.
 8. A power supply substrate that generates anelectro-optical panel driving voltage or a driving voltage to besupplied to a driver that drives the electro-optical panel, based on areference voltage supplied from outside, comprising: a first conductivelayer that transmits the driving voltage, in which at least a portion isformed of a first conductive material; and a second conductive layerthat transmits the reference voltage, in which at least a portion isformed of a second conductive material, the first conductive layer andthe second conductive layer being separated from each other by at leastone insulating layer.
 9. The power supply substrate according to claim8, further comprising: a third conductive layer of which at least aportion is formed of a third conductive material, and that is coupled toa predetermined potential.
 10. The power supply substrate according toclaim 9, an area occupied by the third conductive material in the thirdconductive layer being larger than that occupied by the first conductivematerial in the first conductive layer.
 11. A wiring substrate having adriver that generates a driving signal that drives a plurality ofelectro-optical elements in an electro-optical panel having theplurality of electro-optical elements, comprising: a first connectorthat couples an external device to the wiring substrate; and a secondconnector that couples a power supply substrate that generates a drivingvoltage that drives the plurality of electro-optical elements to thewiring substrate.
 12. The wiring substrate according to claim 11, theplurality of electro-optical elements being arranged between a pluralityof pixel electrodes corresponding to the plurality of electro-opticalelements, respectively, and a common electrode formed in common for theplurality of pixel electrodes, the wiring substrate further comprises:first wiring that supplies the common voltage; and second wiring thatsupplies a driving voltage to the plurality of pixel electrodes, and aline width of the first wiring being larger than that of the secondwiring.
 13. The wiring substrate according to claim 11, the plurality ofelectro-optical elements including a red electro-optical element, agreen electro-optical element, and a blue electro-optical element, theplurality of electro-optical elements being arranged between a pluralityof pixel electrodes corresponding to the plurality of electro-opticalelements, respectively, and a common electrode formed in common for theplurality of pixel electrodes, the wiring substrate further comprising:first wiring that supplies the common voltage;red-electro-optical-element wiring that supplies a driving voltage to apixel electrode corresponding to the red electro-optical element;green-electro-optical-element wiring that supplies a driving voltage toa pixel electrode corresponding to the green electro-optical element;and blue-electro-optical-element wiring that supplies a driving voltageto a pixel electrode corresponding to the blue electro-optical element,and a line width of at least one wiring of thered-electro-optical-element wiring, the green-electro-optical-elementwiring, and the blue-electro-optical-element wiring being different fromthe others.
 14. The wiring substrate according to claim 11, theplurality of electro-optical elements comprise a red electro-opticalelement, a green electro-optical element, and a blue electro-opticalelement, the plurality of electro-optical elements are arranged betweena plurality of pixel electrodes corresponding to the plurality ofelectro-optical elements, respectively, and a common electrode formed incommon for the plurality of pixel electrodes, the wiring substratefurther comprises: first wiring that supplies a common voltage;red-electro-optical-element wiring that supplies a driving voltage to apixel electrode corresponding to the red electro-optical element;green-electro-optical-element wiring that supplies the driving voltageto the pixel electrode corresponding to the green electro-opticalelement; and blue-electro-optical-element wiring that supplies thedriving voltage to the pixel electrode corresponding to the blueelectro-optical element, and a line width of each type of thered-electro-optical-element wiring, the green-electro-optical-elementwiring and the blue-electro-optical-element wiring being set accordingto the luminous efficiencies of the corresponding electro-opticalelements.
 15. The wiring substrate according to claim 11, the pluralityof electro-optical elements including a red electro-optical element, agreen electro-optical element, and a blue electro-optical element, theplurality of electro-optical elements being arranged between a pluralityof pixel electrodes corresponding to the plurality of electro-opticalelements, respectively, and a common electrode formed in common for theplurality of pixel electrodes, the wiring substrate further comprising:first wiring that supplies a common voltage; red-electro-optical-elementwiring that supplies a driving voltage to a pixel electrodecorresponding to the red electro-optical element;green-electro-optical-element wiring that supplies the driving voltageto the pixel electrode corresponding to the green electro-opticalelement; and blue-electro-optical-element wiring that supplies thedriving voltage to the pixel electrode corresponding to the blueelectro-optical element, and a line width of thered-electro-optical-element wiring being larger than those of the greenelectro-optical element and the blue electro-optical element.
 16. Thewiring substrate according to claim 11, the plurality of electro-opticalelements including a red electro-optical element, a greenelectro-optical element, and a blue electro-optical element, theplurality of electro-optical elements being arranged between a pluralityof pixel electrodes corresponding to the plurality of electro-opticalelements, respectively, and a common electrode formed in common for theplurality of pixel electrodes, the wiring substrate further comprising:first wiring that supplies a common voltage; red-electro-optical-elementwiring that supplies a driving voltage to a pixel electrodecorresponding to the red electro-optical element;green-electro-optical-element wiring that supplies the driving voltageto the pixel electrode corresponding to the green electro-opticalelement; and blue-electro-optical-element wiring that supplies thedriving voltage to the pixel electrode corresponding to the blueelectro-optical element, and a line width of thegreen-electro-optical-element wiring being narrower than those of thered-electro-optical-element wiring and the blue-electro-optical-elementwiring.
 17. The wiring substrate according to claim 11, the wiringsubstrate being flexible.
 18. An electro-optical module, comprising: thewiring substrate according to claim 17; and an electro-optical panelcoupled to the wiring substrate, the wiring substrate and theelectro-optical panel being coupled to a connecting portion at one sideof a plurality of sides forming a periphery of the electro-opticalpanel, the wiring substrate including a first portion, and a secondportion formed by bending the wiring substrate and facing the firstportion, the first portion being formed through a supporting member thatsupports the electro-optical panel at a second main surface which isopposed to a first main surface existing in a direction where light fromthe electro-optical panel is emitted, the second portion being formed toallow the first portion to be interposed between the second main surfaceand the second portion, and the driver being interposed between thefirst portion and the second portion.
 19. The electro-optical moduleaccording to claim 18, a first connector and a second connector beingarranged in the second portion.
 20. The electro-optical module accordingto claim 18, a base and a first protrusion protruding from the basebeing formed in the second portion, and the first connector beingarranged at an edge of the first protrusion.
 21. The electro-opticalmodule according to claim 20, a second protrusion protruding from thebase being further formed in the second portion, and the secondconnector being arranged at an edge of the second protrusion.
 22. Theelectro-optical module according to claim 21, further comprising: apower supply substrate coupled through the second connector, the powersupply substrate being formed in the second main surface through thesupporting member and the first portion of the wiring substrate, andbeing arranged closer to the connecting portion of the electro-opticalpanel than the second connector.
 23. The electro-optical moduleaccording to claim 22, the supporting member being attached to the powersupply substrate by a detachable mechanism.
 24. An electronic apparatus,comprising an electro-optical module according to claim 1.